38 METHYL ALCOHOL
in both products, especially those from plastered wines, variable proportions of
calcium tartrate may be found. Crude calcium tavtrate contains, besides calcium
tartrate, small proportions of potassium bitartrate, gypsum, lime, calcium
carbonate and organic matter.
YL (Isoamyl) ALCOHOL
CBH180 = 88
Crude amyl alcohol of commerce constitutes fusel oil, which contains
variable quantities of amyl alcohol (sometimes only 30%) mixed with other
higher alcohols, ethyl alcohol, furfural and other impurities. This fusel
oil is a more or less yellow liquid of repulsive odour.
Pure amyl alcohol of commerce is a colourless or yellowish liquid of
peculiar, rather irritating odour, D o-8i4-(v8i6, b.pt. 129-132°, very slightly
soluble in water, readily in alcohol, ether or benzene. It almost always
* j *./
contains small proportions of furfural and other impurities. The tests to
be made are as follows :
1. Density, Boiling Point.—By the ordinary methods.
2. Residue.—50 c.c., evaporated on a ste;n,n-bath, should leave no
3. Furfural, Aldehydes.—5 c.c., when mixed carefully and with
cooling with an equal volume of pure cone, sulphuric acid, should become
neither brown nor turbid (a slight reddish or yellowish coloration is per-
missible). The same result should be obtained with concentrated caustic
4. Alcohol.—This is detected and determined as in amyl acetate (6).
Sec chapter on Spirits and Liqueurs in Vol. It
CH40 « 32
This is marketed in different qualities : methyl alcohol purist*, is a, colour-
less liquid, I) 0796, b.pt. 66°. Commercial methyl alcohol, (rectified, white
methyl alcohol) is a colourless or yellowish liquid, b.pt. usually 64-67°.
Crude methyl alcohol is a yellowish or brownish liquid with a more; or less
empyreumatic odour and burning taste, distilling mainly between 60°
Distinctive Tests.—(a) CHARACTERS.—Crude methyl alcohol is dis-
tinguished from the rectified alcohol (commercial methyl alcohol)-—which
is colourless or almost so—by its yellowish or brownish tint, it's empyreu-
matic odour, burning taste and its large content (15-25%) of acetone (for
the quantitative determination of acetone, see later).
(b) REACTION WITH SULPHURIC ACID. To 5 c.c. are added, gradually
and with cooling, 5 c.c. of cone, sulphuric acid : pure methyl alcohol assumes
only a slightly yellow coloration, whilst the commercial alcohol,, whether
crude or rectified, gives immediately a brown coloration.ic acid as potassium bitartrate and about 6% as